Electrical discharge machines are used to machine or apply a finish to the surface of a workpiece using electrical discharge texturing (EDT). For example, EDT is used to apply a textured or matt finish to the surface of a work roll. The work roll is used in the rolling of metallic products to produce on the products a complementary textured or matt finish.
A known EDT machine for work rolls comprises a workpiece mounting arrangement comprising mounting parts (headstock, tailstock and steadies) which support and rotate the roll about a roll axis. An electrode head carries an array of electrodes supported within a block of insulating material. The head is positioned to one side of the workpiece, and is moveable, for example by a servo-motor, towards and away from the work roll and is supported by a housing. The housing comprises electrical connections for coupling each electrode to an individual source of pulsed direct current. In use, a gap is defined between the electrodes and the workpiece surface to define a gap. A bath of dielectric fluid is provided so that said fluid is present in the gap. By applying electrical pulses to the electrodes in a controlled manner, electricity flows between the electrodes and the roll surface creating a spark which creates the textured or matt finish.
A collecting bath is provided behind the dielectric bath to catch overspill as the bath is replenished, which overspill is subsequently transmitted back into the bath.
A problem exists however in that fluid which falls from the workpiece itself is not collected efficiently, resulting in wastage, as well as splashing over various surfaces of the machine.